{ "metadata": { "name": "chapter 6.ipynb" }, "nbformat": 3, "nbformat_minor": 0, "worksheets": [ { "cells": [ { "cell_type": "heading", "level": 1, "metadata": {}, "source": [ "Chapter No.6:Torsion" ] }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 6.6.1,Page No.225" ] }, { "cell_type": "code", "collapsed": false, "input": [ "import math\n", "import numpy as np\n", "\n", "#Initilization of Variables\n", "\n", "L=10000 #mm #Length of solid shaft\n", "d=100 #mm #Diameter of shaft\n", "n=150 #rpm\n", "P=112.5*10**6 #N-mm/sec #Power Transmitted\n", "G=82*10**3 #N/mm**2 #modulus of Rigidity\n", "\n", "#Calculations\n", "\n", "J=pi*d**4*(32)**-1 #mm**3 #Polar Modulus\n", "T=P*60*(2*pi*n)**-1 #N-mm #Torsional moment\n", "\n", "r=50 #mm #Radius\n", "\n", "q_s=T*r*J**-1 #N/mm**2 #Max shear stress intensity\n", "Theta=T*L*(G*J)**-1 #angle of twist\n", "\n", "#Result\n", "print\"Max shear stress intensity\",round(q_s,2),\"N/mm**2\"\n", "print\"Angle of Twist\",round(Theta,3),\"radian\"" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Max shear stress intensity 36.48 N/mm**2\n", "Angle of Twist 0.089 radian\n" ] } ], "prompt_number": 1 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 6.6.2,Page No.226" ] }, { "cell_type": "code", "collapsed": false, "input": [ "import math\n", "import numpy as np\n", "\n", "#Initilization of Variables\n", "\n", "P=440*10**6 #N-m/sec #Power transmitted\n", "n=280 #rpm\n", "theta=pi*180**-1 #radian #angle of twist\n", "L=1000 #mm #Length of solid shaft\n", "q_s=40 #N/mm**2 #Max torsional shear stress\n", "G=84*10**3 #N/mm**2 #Modulus of rigidity\n", "\n", "#Calculations\n", "\n", "#P=2*pi*n*T*(60)**-1 #Equation of Power transmitted\n", "T=P*60*(2*pi*n)**-1 #N-mm #torsional moment\n", "\n", "#From Consideration of shear stress\n", "d1=(T*16*(pi*40)**-1)**0.333333 \n", "\n", "#From Consideration of angle of twist\n", "d2=(T*L*32*180*(pi*84*10**3*pi)**-1)**0.25\n", "\n", "#result\n", "print\"Diameter of solid shaft is\",round(d1,2),\"mm\"" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Diameter of solid shaft is 124.09 mm\n" ] } ], "prompt_number": 2 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 6.6.3,Page No.227" ] }, { "cell_type": "code", "collapsed": false, "input": [ "import math\n", "import numpy as np\n", "\n", "#Initilization of Variables\n", "\n", "G=80*10**3 #N/mm**2 #Modulus of rigidity\n", "q_s=80 #N/mm**2 #Max sheare stress\n", "P=736*10**6 #N-mm/sec #Power transmitted\n", "n=200\n", "\n", "#Calculations\n", "\n", "T=P*60*(2*pi*n)**-1 #N-mm #Torsional moment\n", "\n", "#Now From consideration of angle of twist\n", "theta=pi*180**-1\n", "#L=15*d\n", "\n", "d=(T*32*180*15*(pi**2*G)**-1)**0.33333\n", "\n", "#Now corresponding stress at the surface is\n", "q_s2=T*32*d*(pi*2*d**4)**-1\n", "\n", "#Result\n", "print\"Max diameter required is\",round(d,2),\"mm\"\n", "print\"Corresponding shear stress is\",round(q_s2,2),\"N/mm**2\"" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Max diameter required is 156.66 mm\n", "Corresponding shear stress is 46.55 N/mm**2\n" ] } ], "prompt_number": 3 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 6.6.4,Page No.228" ] }, { "cell_type": "code", "collapsed": false, "input": [ "import math\n", "import numpy as np\n", "\n", "#Initilization of Variables\n", "\n", "d=25 #mm #Diameter of steel bar\n", "p=50*10**3 #N #Pull\n", "dell_1=0.095 #mm #Extension of bar\n", "l=200 #mm #Guage Length\n", "T=200*10**3 #N-mm #Torsional moment\n", "theta=0.9*pi*180**-1 #angle of twist\n", "L=250 #mm Length of steel bar\n", "\n", "#Calculations\n", "\n", "A=pi*4**-1*d**2 #Area of steel bar #mm**2\n", "E=p*l*(dell_1*A)**-1 #N/mm**2 #Modulus of elasticity \n", "\n", "J=pi*32**-1*d**4 #mm**4 #Polar modulus\n", "\n", "G=T*L*(theta*J)**-1 #Modulus of rigidity #N/mm**2\n", "\n", "#Now from the relation of Elastic constants\n", "mu=E*(2*G)**-1-1\n", "\n", "#result\n", "print\"The Poissoin's ratio is\",round(mu,3)" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "The Poissoin's ratio is 0.292\n" ] } ], "prompt_number": 4 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 6.6.5,Page No.229" ] }, { "cell_type": "code", "collapsed": false, "input": [ "import math\n", "import numpy as np\n", "\n", "#Initilization of Variables\n", "\n", "L=6000 #mm #Length of circular shaft\n", "d1=100 #mm #Outer Diameter\n", "d2=75 #mm #Inner Diameter\n", "R=100*2**-1 #Radius of shaft\n", "T=10*10**6 #N-mm #Torsional moment\n", "G=80*10**3 #N/mm**2 #Modulus of Rigidity\n", "\n", "#Calculations\n", "\n", "J=pi*32**-1*(d1**4-d2**4) #mm**4 #Polar Modulus \n", "\n", "#Max Shear stress produced\n", "q_s=T*R*J**-1 #N/mm**2\n", "\n", "#Angle of twist\n", "theta=T*L*(G*J)**-1 #Radian\n", "\n", "#Result\n", "print\"MAx shear stress produced is\",round(q_s,2),\"N/mm**2\"\n", "print\"Angle of Twist is\",round(theta,2),\"Radian\"" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "MAx shear stress produced is 74.5 N/mm**2\n", "Angle of Twist is 0.11 Radian\n" ] } ], "prompt_number": 5 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 6.6.6,Page No.229" ] }, { "cell_type": "code", "collapsed": false, "input": [ "import math\n", "import numpy as np\n", "\n", "#Initilization of Variables\n", "\n", "d1=200 #mm #External Diameter of shaft\n", "t=25 #mm #Thickness of shaft\n", "n=200 #rpm\n", "theta=0.5*pi*180**-1 #Radian #angle of twist\n", "L=2000 #mm #Length of shaft\n", "G=84*10**3 #N/mm**2\n", "d2=d1-2*t #mm #Internal Diameter of shaft\n", "\n", "#Calculations\n", "\n", "J=pi*32**-1*(d1**4-d2**4) #mm**4 #Polar Modulus \n", "\n", "#Torsional moment\n", "T=G*J*theta*L**-1 #N/mm**2 \n", "\n", "#Power Transmitted\n", "P=2*pi*n*T*60**-1*10**-6 #N-mm\n", "\n", "#Max shear stress transmitted\n", "q_s=G*theta*(d1*2**-1)*L**-1 #N/mm**2 \n", "\n", "#Result\n", "print\"Power Transmitted is\",round(P,2),\"N-mm\"\n", "print\"Max Shear stress produced is\",round(q_s,2),\"N/mm**2\"" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Power Transmitted is 824.28 N-mm\n", "Max Shear stress produced is 36.65 N/mm**2\n" ] } ], "prompt_number": 6 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 6.6.7,Page No.230" ] }, { "cell_type": "code", "collapsed": false, "input": [ "import math\n", "import numpy as np\n", "\n", "#Initilization of Variables\n", "\n", "P=3750*10**6 #N-mm/sec\n", "n=240 #Rpm\n", "q_s=160 #N/mm**2 #Max shear stress\n", "\n", "#Calculations\n", "\n", "#d2=0.8*d2 #mm #Internal Diameter of shaft\n", "\n", "#J=pi*32**-1*(d1**4-d2**4) #mm**4 #Polar modulus\n", "#After substituting value in above Equation we get\n", "#J=0.05796*d1**4\n", "\n", "T=P*60*(2*pi*n)**-1 #N-mm #Torsional moment\n", "\n", "#Now from Torsion Formula\n", "#T*J**-1=q_s*R**-1 ......................................(1)\n", "\n", "#But R=d1*2**-1 \n", "\n", "#Now substituting value of R and J in Equation (1) we get\n", "d1=(T*(0.05796*q_s*2)**-1)**0.33333\n", "\n", "d2=d1*0.8\n", "\n", "#Result\n", "print\"The size of the Shaft is:d1\",round(d1,3),\"mm\"\n", "print\" :d2\",round(d2,3),\"mm\"" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "The size of the Shaft is:d1 200.362 mm\n", " :d2 160.289 mm\n" ] } ], "prompt_number": 7 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 6.6.8,Page No.231" ] }, { "cell_type": "code", "collapsed": false, "input": [ "import math\n", "import numpy as np\n", "\n", "#Initilization of Variables\n", "\n", "P=245*10**6 #N-mm/sec #Power transmitted\n", "n=240 #rpm\n", "q_s=40 #N/mm**2 #Shear stress\n", "theta=pi*180**-1 #radian #Angle of twist\n", "L=1000 #mm #Length of shaft\n", "G=80*10**3 #N/mm**2\n", "\n", "#Tmax=1.5*T\n", "\n", "#Calculations\n", "\n", "T=P*60*(2*pi*n)**-1 #N-mm #Torsional Moment\n", "Tmax=1.5*T\n", "\n", "#Now For Solid shaft\n", "#J=pi*32*d**4\n", "\n", "#Now from the consideration of shear stress we get\n", "#T*J**-1=q_s*(d*2**-1)**-1\n", "#After substituting value in above Equation we get\n", "#T=pi*16**-1*d**3*q_s\n", "\n", "#Designing For max Torque\n", "d=(Tmax*16*(pi*40)**-1)**0.33333 #mm #Diameter of shaft\n", "\n", "#For max Angle of Twist\n", "#Tmax*J**-1=G*theta*L**-1 \n", "#After substituting value in above Equation we get\n", "d2=(Tmax*32*180*L*(pi**2*G)**-1)**0.25\n", "\n", "#For Hollow Shaft\n", "\n", "#d1_2=Outer Diameter\n", "#d2_2=Inner Diameter\n", "\n", "#d2_2=0.5*d1_2\n", "\n", "# Polar modulus\n", "#J=pi*32**-1*(d1_2**4-d2_2**4)\n", "#After substituting values we get\n", "#J=0.092038*d1_2**4\n", "\n", "#Now from the consideration of stress\n", "#Tmax*J**-1=q_s*(d1_2*2**-1)**-1\n", "#After substituting values and further simplifying we get\n", "d1_2=(Tmax*(0.092038*2*q_s)**-1)**0.33333\n", "\n", "#Now from the consideration of angle of twist\n", "#Tmax*J**-1=G*theta*L**-1\n", "#After substituting values and further simplifying we get\n", "d1_3=(Tmax*180*L*(0.092038*G*pi)**-1)**0.25\n", "\n", "d2_2=0.5*d1_2\n", "\n", "#result\n", "print\"Diameter of shaft is:For solid shaft:d\",round(d,2),\"mm\"\n", "print\" :For Hollow shaft:d1_2\",round(d1_2,3),\"mm\"\n", "print\" : :d2_2\",round(d2_2,3),\"mm\" " ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Diameter of shaft is:For solid shaft:d 123.01 mm\n", " :For Hollow shaft:d1_2 125.69 mm\n", " : :d2_2 62.845 mm\n" ] } ], "prompt_number": 8 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 6.6.11,Page No.235" ] }, { "cell_type": "code", "collapsed": false, "input": [ "import math\n", "import numpy as np\n", "\n", "#Initilization of Variables\n", "\n", "P=250*10**6 #N-mm/sec #Power transmitted\n", "n=100 #rpm\n", "q_s=75 #N/mm**2 #Shear stress\n", "\n", "#Calculations\n", "\n", "#From Equation of Power we have\n", "T=P*60*(2*pi*n)**-1 #N-mm #Torsional moment\n", "\n", "#Now from torsional moment equation we have\n", "#T=j*q_s*(d/2**-1)**-1\n", "#After substituting values in above equation and further simplifying we get\n", "#T=pi*16**-1**d**3*q_s\n", "d=(T*16*(pi*q_s)**-1)**0.3333 #mm #Diameter of solid shaft\n", "\n", "#PArt-2\n", "\n", "#Let d1 and d2 be the outer and inner diameter of hollow shaft\n", "#d2=0.6*d1\n", "\n", "#Again from torsional moment equation we have\n", "#T=pi*32**-1*(d1**4-d2**4)*q_s*(d1/2)**-1\n", "d1=(T*16*(pi*(1-0.6**4)*q_s)**-1)**0.33333\n", "d2=0.6*d1\n", "\n", "#Cross sectional area of solid shaft\n", "A1=pi*4**-1*d**2 #mm**2\n", "\n", "#cross sectional area of hollow shaft\n", "A2=pi*4**-1*(d1**2-d2**2)\n", "\n", "#Now percentage saving in weight\n", "#Let W be the percentage saving in weight\n", "W=(A1-A2)*100*A1**-1\n", "\n", "#Result\n", "print\"Percentage saving in Weight is\",round(W,3),\"%\"\n", "print\"Size of shaft is:solid shaft:d\",round(d,3),\"mm\"\n", "print\" :Hollow shaft:d1\",round(d1,3),\"mm\"\n", "print\" : :d2\",round(d2,3),\"mm\"" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Percentage saving in Weight is 29.735 %\n", "Size of shaft is:solid shaft:d 117.418 mm\n", " :Hollow shaft:d1 123.031 mm\n", " : :d2 73.818 mm\n" ] } ], "prompt_number": 9 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 6.6.12,Page No.237" ] }, { "cell_type": "code", "collapsed": false, "input": [ "import math\n", "import numpy as np\n", "\n", "#Initilization of Variables\n", "d=100 #mm #Diameter of solid shaft\n", "d1=100 #mm #Outer Diameter of hollow shaft\n", "d2=50 #mm #Inner Diameter of hollow shaft\n", "\n", "#Calculations\n", "\n", "#Torsional moment of solid shaft\n", "#T_s=J*q_s*(d*2**-1)**-1 \n", "#After substituting values in above equation and further simplifying we get\n", "#T_s=pi*16*d**3*q_s ...............(1)\n", "\n", "#torsional moment for hollow shaft is\n", "#T_h=J*q_s*(d1**4-d2**4)**-1*(d1*2**-1)\n", "#After substituting values in above equation and further simplifying we get\n", "#T_h=pi*32**-1*2*d1**-1*(d1**4-d2**4)*q_s ...........(2)\n", "\n", "#Dividing Equation 2 by 1 we get\n", "#Let the ratio of T_h*T_s**-1 Be X\n", "X=1-0.5**4\n", "\n", "#Loss in strength \n", "#Let s be the loss in strength\n", "#s=T_s*T_h*100*T_s**-1\n", "#After substituting values in above equation and further simplifying we get\n", "s=(1-0.9375)*100\n", "\n", "#Weight Ratio \n", "#Let w be the Weight ratio\n", "#w=W_h*W_s**-1\n", "\n", "A_h=pi*32**-1*(d1**2-d2**2) #mm**2 #Area of Hollow shaft\n", "A_s=pi*32**-1*d**2 #mm**2 #Area of solid shaft\n", "\n", "w=A_h*A_s**-1 \n", "\n", "#Result\n", "print\"Loss in strength is\",round(s,2)\n", "print\"Weight ratio is\",round(w,2)" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Loss in strength is 6.25\n", "Weight ratio is 0.75\n" ] } ], "prompt_number": 10 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 6.6.13,Page No.239" ] }, { "cell_type": "code", "collapsed": false, "input": [ "import math\n", "import numpy as np\n", "\n", "#Initilization of Variables\n", "T=8 #KN-m #Torque \n", "d=100 #mm #Diameter of portion AB\n", "d1=100 #mm #External Diameter of Portion BC\n", "d2=75 #mm #Internal Diameter of Portion BC\n", "G=80 #KN/mm**2 #Modulus of Rigidity\n", "L1=1500 #mm #Radial Distance of Portion AB\n", "L2=2500 #mm #Radial Distance ofPortion BC\n", "\n", "#Calculations\n", "\n", "R=d*2**-1 #mm #Radius of shaft\n", "\n", "#For Portion AB,Polar Modulus\n", "J1=pi*32**-1*d**4 #mm**4 \n", "\n", "#For Portion BC,Polar modulus \n", "J2=pi*32**-1*(d1**4-d2**4) #mm**4\n", "\n", "#Now Max stress occurs in portion BC since max radial Distance is sme in both cases\n", "q_max=T*J2**-1*R*10**6 #N/mm**2 \n", "\n", "#Let theta1 be the rotation in Portion AB and theta2 be the rotation in portion BC\n", "theta1=T*L1*(G*J1)**-1 #Radians\n", "theta2=T*L2*(G*J2)**-1 #Radians\n", "\n", "#Total Rotational at end C\n", "theta=(theta1+theta2)*10**3 #Radians\n", "\n", "#Result\n", "print\"Max stress induced is\",round(q_max,2),\"N/mm**2\"\n", "print\"Angle of Twist is\",round(theta,3),\"radians\"" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Max stress induced is 59.6 N/mm**2\n", "Angle of Twist is 0.053 radians\n" ] } ], "prompt_number": 11 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 6.6.14,Page No.240" ] }, { "cell_type": "code", "collapsed": false, "input": [ "import math\n", "import numpy as np\n", "\n", "#Initilization of Variables\n", "\n", "q_b=80 #N/mm**2 #Shear stress in Brass\n", "q_s=100 #N/mm**2 #Shear stress in Steel\n", "G_b=40*10**3 #N/mm**2 \n", "G_s=80*10**3 \n", "L_b=1000 #mm #Length of brass shaft\n", "L_s=1200 #mm #Length of steel shaft\n", "d1=80 #mm #Diameter of brass shaft\n", "d2=60 #mm #Diameter of steel shaft\n", "\n", "#Calculations\n", "\n", "#Polar modulus of brass rod\n", "J_b=pi*32**-1*d1**4 #mm**4 \n", "\n", "#Polar modulus of steel rod\n", "J_s=pi*32**-1*d2**4 #mm**4\n", "\n", "#Considering bras Rod:AB\n", "T1=J_b*q_b*(d1*2**-1)**-1 #N-mm \n", "\n", "#Considering Steel Rod:BC\n", "T2=J_s*q_s*(d2*2**-1)**-1 #N-mm\n", "\n", "#Max Torque that can be applied\n", "T2\n", "\n", "#Let theta_b and theta_s be the rotations in Brass and steel respectively\n", "theta_b=T2*L_b*(G_b*J_b)**-1 #Radians\n", "theta_s=T2*L_s*(G_s*J_s)**-1 #Radians\n", "\n", "theta=theta_b+theta_s #Radians #Rotation of free end\n", "\n", "#Result\n", "print\"Total of free end is\",round(theta,3),\"Radians\"" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Total of free end is 0.076 Radians\n" ] } ], "prompt_number": 12 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 6.6.15,Page No.241" ] }, { "cell_type": "code", "collapsed": false, "input": [ "import math\n", "import numpy as np\n", "\n", "#Initilization of Variables\n", "\n", "G=80*10**3 #N/mm**2 #Modulus of Rigidity\n", "d1=100 #mm #Outer diameter of hollow shft\n", "d2=80 #mm #Inner diameter of hollow shaft\n", "d=80 #mm #diameter of Solid shaft\n", "d3=60 #mm #diameter of Solid shaft having L=0.5m\n", "L1=300 #mm #Length of Hollow shaft\n", "L2=400 #mm #Length of solid shaft\n", "L3=500 #mm #LEngth of solid shaft of diameter 60mm\n", "T1=2*10**6 #N-mm #Torsion in Shaft AB\n", "T2=1*10**6 #N-mm #Torsion in shaft BC\n", "T3=1*10**6 #N-mm #Torsion in shaft CD\n", "\n", "#Calculations\n", "\n", "#Now Polar modulus of section AB\n", "J1=pi*32**-1*(d1**4-d2**4) #mm**4 \n", "\n", "#Polar modulus of section BC\n", "J2=pi*32**-1*d**4 #mm**4\n", "\n", "#Polar modulus of section CD\n", "J3=pi*32**-1*d3**4 #mm**4\n", "\n", "#Now angle of twist of AB\n", "theta1=T1*L1*(G*J1)**-1 #radians\n", "\n", "#Angle of twist of BC\n", "theta2=T2*L2*(G*J2)**-1 #radians\n", "\n", "#Angle of twist of CD\n", "theta3=T3*L3*(G*J3)**-1 #radians\n", "\n", "#Angle of twist\n", "theta=theta1-theta2+theta3 #Radians\n", "\n", "#Shear stress in AB From Torsion Equation\n", "q_s1=T1*(d1*2**-1)*J1**-1 #N/mm**2 \n", "\n", "#Shear stress in BC\n", "q_s2=T2*(d*2**-1)*J2**-1 #N/mm**2 \n", "\n", "#Shear stress in CD\n", "q_s3=T3*(d3*2**-1)*J3**-1 #N-mm**2\n", "\n", "#As max shear stress occurs in portion CD,so consider CD\n", "\n", "#Result\n", "print\"Angle of twist at free end is\",round(theta,5),\"Radian\"\n", "print\"Max Shear stress\",round(q_s3,2),\"N/mm**2\"" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Angle of twist at free end is 0.00496 Radian\n", "Max Shear stress 23.58 N/mm**2\n" ] } ], "prompt_number": 13 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 6.6.16,Page No.242" ] }, { "cell_type": "code", "collapsed": false, "input": [ "import math\n", "import numpy as np\n", "\n", "#Initilization of Variables\n", "\n", "L=1000 #mm #Length of bar\n", "L1=600 #mm #Length of Bar AB\n", "L2=400 #mm #Length of Bar BC\n", "d1=60 #mm #Outer Diameter of bar BC\n", "d2=30 #mm #Inner Diameter of bar BC\n", "d=60 #mm #Diameter of bar AB\n", "T=2*10**6 #N-mm #Total Torque\n", "\n", "#Calculations\n", "\n", "#Polar Modulus of Portion AB\n", "J1=pi*32**-1*d**4 #mm*4\n", "\n", "#Polar Modulus of Portion BC\n", "J2=pi*32**-1*(d1**4-d2**4) #mm**4\n", "\n", "#Let T1 be the torque resisted by bar AB and T2 be torque resisted by Bar BC\n", "#Let theta1 and theta2 be the rotation of shaft in portion AB & BC\n", "\n", "#theta1=T1*L1*(G*J1)**-1 #radians\n", "#After substituting values and further simplifying we get \n", "#theta1=32*600*T1*(pi*60**4*G)**-1\n", "\n", "#theta2=T2*L*(J2*G)**-1 #Radians\n", "#After substituting values and further simplifying we get \n", "#theta2=32*400*T2*(pi*60**4*(1-0.5**4)*G)**-1 \n", "\n", "#Now For consistency of Deformation,theta1=theta2\n", "#After substituting values and further simplifying we get \n", "#T1=0.7111*T2 ..................................................(1)\n", "\n", "#But T1+T2=T=2*10**6 ...........................................(2)\n", "#Substituting value of T1 in above equation\n", "\n", "T2=T*(0.7111+1)**-1\n", "T1=0.71111*T2\n", "\n", "#Max stress in Portion AB\n", "q_s1=T1*(d*2**-1)*(J1)**-1 #N/mm**2\n", "\n", "#Max stress in Portion BC\n", "q_s2=T2*(d1*2**-1)*J2**-1 #N/mm**2 \n", "\n", "#Result\n", "print\"Stresses Developed in Portion:AB\",round(q_s1,2),\"N/mm**2\"\n", "print\" :BC\",round(q_s2,2),\"N/mm**2\"" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Stresses Developed in Portion:AB 19.6 N/mm**2\n", " :BC 29.4 N/mm**2\n" ] } ], "prompt_number": 14 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 6.6.17,Page No.243" ] }, { "cell_type": "code", "collapsed": false, "input": [ "import math\n", "import numpy as np\n", "\n", "#Initilization of Variables\n", "\n", "d1=80 #mm #External Diameter of Brass tube\n", "d2=50 #mm #Internal Diameter of Brass tube\n", "d=50 #mm #Diameter of steel Tube\n", "G_b=40*10**3 #N/mm**2 #Modulus of Rigidity of brass tube\n", "G_s=80*10**3 #N/mm**2 #Modulus of rigidity of steel tube\n", "T=6*10**6 #N-mm #Torque\n", "L=2000 #mm #Length of Tube\n", "\n", "#Calculations\n", "\n", "#Polar Modulus of brass tube\n", "J1=pi*32**-1*(d1**4-d2**4) #mm**4 \n", "\n", "#Polar modulus of steel Tube\n", "J2=pi*32**-1*d**4 #mm**4\n", "\n", "#Let T_s & T_b be the torque resisted by steel and brass respectively\n", "#Then, T_b+T_s=T ............................................(1)\n", "\n", "#Since the angle of twist will be the same\n", "#Theta1=Theta2\n", "#After substituting values and further simplifying we get \n", "#Ts=0.360*Tb ...........................................(2)\n", "\n", "#After substituting value of Ts in eqn 1 and further simplifying we get \n", "T_b=T*(0.36+1)**-1 #N-mm\n", "T_s=0.360*T_b\n", "\n", "#Let q_s and q_b be the max stress in steel and brass respectively\n", "q_b=T_b*(d1*2**-1)*J1**-1 #N/mm**2\n", "q_s=T_s*(d2*2**-1)*J2**-1 #N/mm**2\n", "\n", "#Since angle of twist in brass=angle of twist in steel\n", "theta_s=T_s*L*(J2*G_s)**-1\n", "\n", "#Result\n", "print\"Stresses Developed in Materials are:Brass\",round(q_b,2),\"N/mm**2\"\n", "print\" :Steel\",round(q_s,2),\"N/mm**2\"\n", "print\"Angle of Twist in 2m Length\",round(theta_s,3),\"Radians\" " ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Stresses Developed in Materials are:Brass 51.79 N/mm**2\n", " :Steel 64.71 N/mm**2\n", "Angle of Twist in 2m Length 0.065 Radians\n" ] } ], "prompt_number": 15 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 6.6.18,Page No.245" ] }, { "cell_type": "code", "collapsed": false, "input": [ "import math\n", "import numpy as np\n", "\n", "#Initilization of Variables\n", "\n", "d1=60 #mm #External Diameter of aluminium Tube\n", "d2=40 #mm #Internal Diameter of aluminium Tube\n", "d=40 #mm #Diameter of steel tube\n", "q_a=60 #N/mm**2 #Permissible stress in aluminium\n", "q_s=100 #N/mm**2 #Permissible stress in steel tube\n", "G_a=27*10**3 #N/mm**2 \n", "G_s=80*10**3 #N/mm**2 \n", "\n", "#Calculations\n", "\n", "#Polar modulus of aluminium Tube\n", "J_a=pi*32**-1*(d1**4-d2**4) #mm**4\n", "\n", "#Polar Modulus of steel Tube\n", "J_s=pi*32**-1*d**4 #mm**4\n", "\n", "#Now the angle of twist of steel tube = angle of twist of aluminium tube\n", "#T_s*L_s*(J_s*theta_s)**-1=T_a*L_a*(J_a*theta_a)**-1\n", "#After substituting values in above Equation and Further simplifyin we get\n", "#T_s=0.7293*T_a .....................(1)\n", "\n", "#If steel Governs the resisting capacity\n", "T_s1=q_s*J_s*(d*2**-1)**-1 #N-mm\n", "T_a1=T_s1*0.7293**-1 #N-mm\n", "T1=(T_s1+T_a1)*10**-6 #KN-m #Total Torque in steel Tube\n", "\n", "#If aluminium Governs the resisting capacity \n", "T_a2=q_a*J_a*(d1*2**-1) #N-mm\n", "T_s2=T_a2*0.7293 #N-mm\n", "T2=(T_s2+T_a2)*10**-6 #KN-m #Total Torque in aluminium tube\n", "\n", "#Result\n", "print\"Steel Governs the torque carrying capacity\",round(T1,2),\"KN-m\"" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Steel Governs the torque carrying capacity 2.98 KN-m\n" ] } ], "prompt_number": 16 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 6.6.19,Page No.247" ] }, { "cell_type": "code", "collapsed": false, "input": [ "import math\n", "import numpy as np\n", "\n", "#Initilization of Variables\n", "\n", "P=225*10**6 #N-mm/sec #Power Trasmitted\n", "q_b=80 #N/mm**2 #Shear stress\n", "n=200 #Rpm\n", "q_k=100 #N/mm**2 #PErmissible stress in Keys\n", "D=300 #mm #Diameter of bolt circle\n", "L=150 #mm #Length of shear key\n", "d=16 #mm #Diameterr of bolt\n", "\n", "#Calculations\n", "T=60*P*(2*pi*n)**-1 #N-mm #Torque\n", "\n", "#Now From Torsion Formula\n", "#T*J**-1=q_s*R**-1\n", "#After substituting values we get\n", "#T=pi*16*d**3*n\n", "#After further simplifying we get\n", "d1=(T*16*(pi*q_s)**-1)**0.33333\n", "\n", "#Let b be the width of shear Key\n", "#T=q_k*L*b*R\n", "#After simplifying further we get\n", "b=T*(q_k*L*(d1*2**-1))**-1 #mm\n", "\n", "#Let n2 be the no. of bolts required at bolt circle of radius\n", "R_b=D*2**-1 #mm \n", "\n", "n2=T*4*(q_b*pi*d**2*R_b)**-1\n", "\n", "#result\n", "print\"Minimum no. of Bolts Required are\",round(n2,2)" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Minimum no. of Bolts Required are 4.45\n" ] } ], "prompt_number": 17 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 6.6.20,Page No.250" ] }, { "cell_type": "code", "collapsed": false, "input": [ "import math\n", "import numpy as np\n", "\n", "#Initilization of Variables\n", "\n", "T=2*10**6 #N-mm #Torque transmitted\n", "G=80*10**3 #N/mm**2 #Modulus of rigidity\n", "d1=40 #mm \n", "d2=80 #mm\n", "r1=20 #mm\n", "r2=40 #mm\n", "L=2000 #mm #Length of shaft\n", "\n", "#Calculations\n", "\n", "#Angle of twist \n", "theta=2*T*L*(r1**2+r1*r2+r2**2)*(3*pi*G*r2**3*r1**3)**-1 #radians\n", "\n", "#If the shaft is treated as shaft of average Diameter\n", "d_avg=(d1+d2)*2**-1 #mm\n", "\n", "theta1=T*L*(G*pi*32**-1*d_avg**4)**-1 #Radians\n", "\n", "#Percentage Error\n", "#Let Percentage Error be E\n", "X=theta-theta1\n", "E=(X*theta**-1)*100 \n", "\n", "#Result\n", "print\"Percentage Error is\",round(E,2),\"%\"" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Percentage Error is 32.28 %\n" ] } ], "prompt_number": 18 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 6.6.21,Page No.252" ] }, { "cell_type": "code", "collapsed": false, "input": [ "import math\n", "import numpy as np\n", "\n", "#Initilization of Variables\n", "\n", "G=80*10**3 #N/mm**2 \n", "P=1*10**9 #N-mm/sec #Power\n", "n=300 \n", "d1=150 #mm #Outer Diameter\n", "d2=120 #mm #Inner Diameter\n", "L=2000 #mm #Length of circular shaft\n", "\n", "#Calculations\n", "\n", "T=P*60*(2*pi*n)**-1 #N-mm\n", "\n", "#Polar Modulus \n", "J=pi*32**-1*(d1**4-d2**4) #mm**4\n", "\n", "q_s=T*J**-1*(d1*2**-1) #N/mm**2 \n", "\n", "\n", "#Strain ENergy\n", "U=q_s**2*(4*G)**-1*pi*4**-1*(d1**2-d2**2)*L\n", "\n", "#Result\n", "print\"Max shear stress is\",round(q_s,2),\"N/mm**2\"\n", "print\"Strain Energy stored in the shaft is\",round(U,2),\"N-mm\"" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Max shear stress is 81.36 N/mm**2\n", "Strain Energy stored in the shaft is 263181.37 N-mm\n" ] } ], "prompt_number": 19 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 6.6.22,Page No.254" ] }, { "cell_type": "code", "collapsed": false, "input": [ "import math\n", "import numpy as np\n", "\n", "#Initilization of Variables\n", "\n", "d=12 #mm #Diameter of helical spring\n", "D=150 #mm #Mean Diameter\n", "R=D*2**-1 #mm #Radius of helical spring\n", "n=10 #no.of turns\n", "G=80*10**3 #N/mm**2 \n", "W=450 #N #Load\n", "\n", "#Calculations\n", "\n", "#Max shear stress \n", "q_s=16*W*R*(pi*d**3)**-1 #N/mm**2\n", "\n", "#Strain Energy stored\n", "U=32*W**2*R**3*n*(G*d**4)**-1 #N-mm\n", "\n", "#Deflection Produced\n", "dell=64*W*R**3*n*(G*d**4)**-1 #mm\n", "\n", "#Stiffness Spring\n", "k=W*dell**-1 #N/mm\n", "\n", "#Result\n", "print\"Max shear stress is\",round(q_s,2),\"N/mm**2\"\n", "print\"Strain Energy stored is\",round(U,2),\"N-mm\"\n", "print\"Deflection Produced is\",round(dell,2),\"mm\"\n", "print\"Stiffness spring is\",round(k,2),\"N/mm\"" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Max shear stress is 99.47 N/mm**2\n", "Strain Energy stored is 16479.49 N-mm\n", "Deflection Produced is 73.24 mm\n", "Stiffness spring is 6.14 N/mm\n" ] } ], "prompt_number": 20 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 6.6.23,Page No.255" ] }, { "cell_type": "code", "collapsed": false, "input": [ "import math\n", "import numpy as np\n", "\n", "#Initilization of Variables\n", "\n", "K=5 #N/mm #Stiffness\n", "L=100 #mm #Solid Length\n", "q_s=60 #N/mm**2 #Max shear stress\n", "W=200 #N #Max Load\n", "G=80*10**3 #N/mm**2\n", "\n", "#Calculations\n", "\n", "#K=W*dell**-1\n", "#After substituting values and further simplifying we get\n", "#d=0.004*R**3*n ........(1) #mm #Diameter of wire\n", "#n=L*d**-1 ........(2)\n", "\n", "#From Shearing stress\n", "#q_s=16*W*R*(pi*d**3)**-1 \n", "#After substituting values and further simplifying we get\n", "#d**4=0.004*R**3*n .................(4)\n", "\n", "#From Equation 1,2,3\n", "#d**4=0.004*(0.0785*d**3)**3*100*d**-1\n", "#after further simplifying we get\n", "d=5168.101**0.25\n", "n=100*d**-1\n", "R=(d**4*(0.004*n)**-1)**0.3333\n", "\n", "#Result\n", "print\"Diameter of Wire is\",round(d,2),\"mm\"\n", "print\"No.of turns is\",round(n,2)\n", "print\"Mean Radius of spring is\",round(R,2),\"mm\"" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Diameter of Wire is 8.48 mm\n", "No.of turns is 11.79\n", "Mean Radius of spring is 47.83 mm\n" ] } ], "prompt_number": 21 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 6.6.24,Page No.255" ] }, { "cell_type": "code", "collapsed": false, "input": [ "import math\n", "import numpy as np\n", "\n", "#Initilization of Variables\n", "\n", "m=5*10**5 #Wagon Weighing\n", "v=18*1000*36000**-1 \n", "d=300 #mm #Diameter of Beffer springs\n", "n=18 #no.of turns\n", "G=80*10**3 #N/mm**2\n", "dell=225\n", "R=100 #mm #Mean Radius\n", "\n", "#Calculations\n", "\n", "#Energy of Wagon\n", "E=m*v**2*(9.81*2)**-1 #N-mm\n", "\n", "#Load applied\n", "W=dell*G*d**4*(64*R**3*n)**-1 #N \n", "\n", "#Energy each spring can absorb is\n", "E2=W*dell*2**-1 #N-mm\n", "\n", "#No.of springs required to absorb energy of Wagon\n", "n2=E*E2**-1 *10**7\n", "\n", "#Result\n", "print\"No.of springs Required for Buffer is\",round(n2,2)" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "No.of springs Required for Buffer is 4.47\n" ] } ], "prompt_number": 22 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 6.6.25,Page No.259" ] }, { "cell_type": "code", "collapsed": false, "input": [ "import math\n", "import numpy as np\n", "\n", "#Initilization of Variables\n", "\n", "b=180 #mm #width of flange\n", "d=10 #mm #Depth of flange\n", "t=10 #mm #Thickness of flange\n", "D=400 #mm #Overall Depth \n", "\n", "#Calculations\n", "\n", "I_xx=1*12**-1*(b*D**3-(b-t)*(D-2*d)**3)\n", "I_yy=1*12**-1*((D-2*d)*t**3+2*t*b**3)\n", "\n", "#If warping is neglected\n", "J=I_xx+I_yy #mm**4\n", "\n", "#Since b/d>1.6,we get\n", "J2=1*3**-1*d**3*b*(1-0.63*d*b**-1)*2+1*3**-1*t**3*(D-2*d)*(1-0.63*t*b**-1)\n", "\n", "#Over Estimation of torsional Rigidity would have been \n", "T=J*J2**-1\n", "\n", "#Result\n", "print\"Error in assessing torsional Rigidity if the warping is neglected is\",round(T,2)\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Error in assessing torsional Rigidity if the warping is neglected is 808.28\n" ] } ], "prompt_number": 23 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 6.6.26,Page No.261" ] }, { "cell_type": "code", "collapsed": false, "input": [ "import math\n", "import numpy as np\n", "\n", "#Initilization of Variables\n", "\n", "d1=100 #mm #Outer Diameter\n", "d2=95 #mm #Inner Diameter\n", "T=2*10**6 #N-mm #Torque\n", "\n", "#Calculations\n", "\n", "J=pi*32**-1*(d1**4-d2**4) #mm**4 #Polar Modulus\n", "\n", "#Shear stress\n", "q_max=T*J**-1*d1*2**-1 #N/mm**2 \n", "\n", "#Now theta*L**-1=T*(G*J)**-1\n", "#After substituting values and further simplifying we get\n", "#Let theta*L**-1=X\n", "X=T*J**-1\n", "\n", "#Now Treating it as very thin walled tube\n", "d=(d1+d2)*2**-1 #mm\n", "\n", "r=d*2**-1 \n", "t=(d1-d2)*2**-1\n", "q_max2=T*(2*pi*r**2*t)**-1 #N/mm**2\n", "\n", "X2=T*(2*pi*r**3*t)**-1 \n", "\n", "#Result\n", "print\"When it is treated as hollow shaft:Max shear stress\",round(q_max,2),\"N/mm**2\"\n", "print\" :Angle of Twist per unit Length\",round(X,3)\n", "print\"When it is very thin Walled Tube :Max shear stress\",round(q_max2,2),\"N/mm**2\"\n", "print\" :Angle of twist per Unit Length\",round(X2,3)" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "When it is treated as hollow shaft:Max shear stress 54.91 N/mm**2\n", " :Angle of Twist per unit Length 1.098\n", "When it is very thin Walled Tube :Max shear stress 53.57 N/mm**2\n", " :Angle of twist per Unit Length 1.099\n" ] } ], "prompt_number": 24 } ], "metadata": {} } ] }